Stroke Risk May Be Higher with CABG

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This meta-analysis of 19 randomized trials points to percutaneous coronary intervention as associated with a lower risk of stroke at 30 days and 12 months compared with coronary artery bypass graft surgery.

Note that use of aggregate data did not allow for analysis of traditional risk factors for stroke such as diabetes or prior history of stroke.

Reopening blocked coronary arteries with CABG instead of percutaneous coronary intervention (PCI) is associated with a greater risk of stroke up to about 1 year after the procedure, a meta-analysis showed.

In pooled results of randomized trials, the 30-day rate of stroke was 1.2% after CABG and 0.34% after PCI (OR 2.94, 95% CI 1.69 to 5.09), according to Gregg Stone, MD, of Columbia University in New York City, and colleagues.

That difference was sustained at a median follow-up of 12.1 months (1.83% versus 0.99%; OR 1.67, 95% CI 1.09 to 2.56), the researchers reported in the Aug. 28 issue of the Journal of the American College of Cardiology.

The period during which the studies were performed and the severity of the coronary artery disease did not have a significant effect on the findings.

"The large number of patients included in this study and the satisfaction of all requirements for meta-analysis, in terms of low heterogeneity, absent publication bias, and sensitivity analysis, provide robust scientific validity to our findings, which can assist informed decision making by patients, their families, and physicians when deciding on the optimal strategy of revascularization in patients with severe coronary artery disease," Stone and colleagues wrote.

There have been suggestions in randomized trials that the risk of stroke is higher after CABG than after PCI, although only one trial -- SYNTAX -- has shown a significantly elevated stroke risk with surgery. Most of the trials lacked sufficient statistical power to find a difference in stroke rates.

To explore the issue, the researchers performed a meta-analysis of 19 trials that included 10,944 patients randomized to CABG or PCI. The patients had single-vessel, multivessel, or unprotected left main coronary artery disease.

The meta-analysis revealed that CABG was associated with a higher stroke rate. The number needed to harm was 155, with seven excess strokes for every 1,000 patients who underwent surgery instead of PCI.

The odds ratios for stroke when comparing CABG with PCI were highest for patients with unprotected left main disease and lowest for those with single-vessel disease, although the interaction between severity of disease and the relative increase in stroke risk was not significant at either 30 days or 1 year (P>0.05 for both).

Similar results were seen in a meta-analysis of 27 observational studies that included 33,980 patients.

"The results in these real-world patients were consistent with those from the randomized controlled trials, providing support that the observed differences in stroke between CABG and PCI are real," the researchers wrote.

They acknowledged some limitations of their analysis, however, including the relative short duration of follow-up, the lack of a uniform stroke definition among the included studies, and the inability to analyze the relationship between stroke and mortality or to evaluate the impact of traditional risk factors for stroke because of the use of aggregate data.

Stone is a consultant to Abbott Vascular, Boston Scientific, and Medtronic. One of his co-authors has received speaker honoraria from Abbott Vascular, Boston Scientific, Cordis, and Medtronic. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.